The present invention relates to stop pieces for limiting angular travel about an axis of a first element with respect to a second element.
Many articulated systems use such elements which are movable in rotation with respect to one another.
For matters relating to the occupation of the surrounding space or the transmission of power, data or fluids, the angular travel between these elements must be limited, in both directions of rotation, by stop pieces.
Conventionally, these stop pieces are rigid, which results, depending on the masses and speeds of displacement of the elements, in sudden stops against stop pieces, which generate vibrations and are very often noisy.
Furthermore, the repeated shocks and the inertias brought into play rapidly bring the safety of the system into question.
The purpose of the present invention is to propose a flexible stop piece providing limitation of angular travel without shocks between two elements and a progressive braking of the movement of relative rotation between these two elements, whilst eliminating the abovementioned disadvantages of fixed stop pieces.
In order to achieve this, according to one aspect of the invention, the first element comprises an inner part extending coaxially with respect to the axis of rotation in a sleeve part of the second element, the stop piece furthermore comprising an elastic element with two helical coils both wound in the same direction and one on each side of a central connecting zone, disposed concentrically between the inner part and the sleeve part, each coil being terminated with an end part, the sleeve part comprising a first stop zone capable of coming to bear against the central zone of the spring, the inner part comprising at least a second and a third stop zone, each capable of coming to bear against a corresponding end part of the elastic element.
According to other more particular characteristics of the invention:
the second and third stop zones are offset angularly;
each coil is disposed around the inner part such that it is normally slack;
the end parts extend axially and/or radially.
The present invention also relates to an articulated system comprising at least one such flexible stop piece and typically at least one flexible pipe or conductor extending inside the first and second elements.
The present invention also relates to a medical equipment item comprising at least one such articulated system.